Frameworks like bootstrap have one big advantage: less creative surface, more get things done surface. They are getting lost not because they don’t know css. They don’t know what was on your mind when you wrote it, and they usually have neither a clue, nor clear documentation, no comments, no common practice guide. Nothing. It is just a wall of fragile definitions already crippled by some previous maintainer to the level when any change explodes into a refactoring of a 20-page interdependent mess. Any negative effect of a framework is heavily offset by the fact that any handcrafted css is eventually fucked up (if not right away), and it is not even negative if a framework helps avoiding it.